Vania



NT OFFICE...

CHARLES H. BREERWOOD, OF PHILADELPHIA, PENNSYLVANIA, ASSIGNOR TO COPLAY CEMENT MANUFACTURING COMPANY, A CORPORATION OF PENNSYL- VANIA.

PROCESS FOR MAKING DOLOMITE BRICKS.

No Drawing.

T 0 all whom it may concern:

Be it known that I, CHARLES H. BREER- wooD, a citizen of the United States, and a resident of Philadelphia, in the county of Philadelphia and State of Pennsylvania, have invented certain new and useful Improvements in Processes for Making Dolomite Bricks, of which the following is a specification.

My invention relates to dolomite bricks and to the process for making the same. It has for its object to form bricks of dolomite adapted to be used in furnaces, and especially in those furnaces where a very high heat is employed such as rotary kilns, steel furnaces and the like. It consists of the improved process herein shown and described.

Although numerous attempts have heretofore been made to use dolomite bricks in furnaces, such as rotary kilns, steel furnaces and the like, it has heretofore not been possible to make dolomite bricks capable of successful use in such furnaces. This has been due mainly to the presence in the finished bricks of moisture, air or other gases which, under the high heat of the furnace, tend to rapidly disrupt the bricks. I have succeeded in making bricks ,which are free from all these internal disturbing factors, and which can be practically and successfully used in such furnaces. Heretofore also the particles of such bricks as have been made have been solarge that the finished bricks readily absorbed air and gases, such air and gases penetrating into the interior of the brick between the particles with the effect that, under the heat of the furnace, the brick is rapidly disrupted. My improved brick, due to the fineness of the particles and their vitrification and compression, can not be penetrated by air and gases.

Generally speaking my improved process consists in vitrifying or amalgamating under high heat, a mixture of dolomite with a small percentage of iron in a finely ground or divided condition, subjecting the mixture in a finely divided state to great pressure to compress it into brick form, and in vitrifying the compressed brick at a high temperature.

Referring to my improved process in its preferred form, I take dolpmite and grind Specification of Letters Patent.

Patented June '7, 1921.

Application filed July 5, 1919. Serial No. 308,823.

it exceedingly fine, preferably 80% through a 200 sieve or finer. The finer the material is ground the better the results will usually be. I mix this with a small percentage of lron, preferably four to seven per cent., grinding the two together to intimately mix them. I then burn the mixture at a high heat, preferably 8000 F. or higher, until the particles are thoroughly vitrified or amalgamated. A practical test to determine whether or not the material is prop erly vitrified, is to submerge it in boiling water for an hour. If there is no disintegration during that time, the material is properly prepared. I then preferably regrind it exceedingly fine, preferably 85%, or higher, through a No. 200 sieve. I then place the finely ground mixture in a mold of the proper shape and subject it to great pressure. I preferably use hydraulic pressure from twenty to thirty tons per square inch. This pressure is preferably exerted at both ends of the brick. I have found that if the brick is compressed from one end only, that the other end is apt not to be sufiiciently compressed. The compression from both ends at the same time relieves of the necessity of the use of a very great pressure and of the very heavy and expensive machinery that would be necessary to exert the pressure required if that were exerted only at one end of the brick. I then burn the compressed brick at a high temperature, preferably at a temperature of 3000 F. or higher.

The amount of iron mixed in and ground with the dolomite runs from four to seven per cent, of the total raw material. In finished bricks it amounts from eight to fourteen per cent.

It will be noted that in my process I use no binder whatever for holding the material together either during the step of compressstruction of the brick. This is due to the fact that the binder element introduced, such for example as water, can not be entirely eliminated, and its presence in the interior of the brick tends, under the high heat of the furnace, to rapid disintegration of the brick.

Before grinding the material in my improved process as described in the specifi cation, I preferably heat it to drive off any absorbed carbonic acid gas or water.

My new and improved product and apparatus, shown and described herein, are not claimed in this application, applicant intending to claim them in divisional applications hereof.

What I claim as new and desire to secure by Letters Patent, is:

1. The process of making dolomite bricks which consists in grinding dolomite containing a small amount of iron exceedingly fine, burning the mixture at a sufficiently high temperature to amalgamate or vitrify it, re-grinding the burnt mixture exceedingly fine, compressing it under great pressure into the desired shape and burning it at a temperature sufficiently high to amalgamate and vitrify the brick.

2. The process of making dolomite bricks which consists in compressing under great pressure vitrified dolomite, containing a small amount of iron, ground exceedingly fine, to form a compressed brick, and burning the brick at a sufiiciently high temperature to amalgamate or vitrify it.

3. The process of making dolomite bricks which consists in grinding dolomite exceedingly fine, mixing with it a small amount of iron, burning the mixture at a high temperature suflicient to amalgamate and vitrify it, regrinding the burnt mixture exceedingly fine, subjecting it to great pressure to form a compressed brick, and burning the brick at a high temperature suflicient to amalgamate and vitrify it.

4. The process of making dolomite bricks which consists in grinding dolomite exceedingly fine, mixing with it a small amount of iron, burning the mixture at a high temperature sufiicient to amalgamate and vitrify it, regrinding the burnt mixture exceedingly fine, forming it into the desired shape, subjecting it to great pressure to form a compressed brick, and burning the brick at a high temperature sufiicient to amalgamate and vitrify it.

5. The process of making dolomite bricks which consists in pressing into brick form under great pressure a finely ground nonhydrous vitrified mixture of dolomite containing a small amount of iron, the mixture being free from air or gases, and subjecting the brick in compressed form to a sufficiently high temperature to amalgamate or vitrify it.

6. The process of making dolomite bricks which consists in grinding dolomite exceedingly fine, mixing with it an amount of iron suflicient to make the iron about four to seven per cent. of the mixture, burning the mixture at a high temperature sufficient to amalgamate and vitrify it, re-grinding the burnt mixture exceedingly fine, subjecting it to great pressure to form a compressed brick, and burning the brick at a high temperature sufficient to amalgamate and vitrify it.

7. The process of making dolomite bricks which consists in placing vitrified dolomite containing a small amount of iron, ground exceedingly fine, in a mold, compressing said material from both ends under high pressure to form a compressed brick, and burn ing the brick at a sufiiciently high temperature to amalgamate or vitrify it.

8. The process of making dolomite bricks which consists in grinding dolomite exceedingly fine, mixing with it a small amount of iron, burning'the mixture at a high temperature sufficient to amalgamate and vitrify it, re-grinding the burnt mixture exceedingly fine, subjecting it in a mold to great pressure at both ends to form a compressed brick, and burning the brick at a high temperature suflicient to amalgamate and vitrify it.

9. A process of making dolomite brick which consists in compressing into brick form under great pressure and from both ends, a finely ground non-hydrous vitrified mixture of dolomite containing a small amount of iron, the mixture being free from air or gases, and subjecting the brick in its compressed form to a suliiciently high temperature to amalgamate or vitrify it.

In testimony whereof, I have signed my name to this specification.

CHARLES H. BREERWOOD. 

